Variable meter shunt

ABSTRACT

A shunt device for milliammeters and the like. This device consists primarily of a slotted plastic member having a low resistance wire in one leg and a high resistance wire in the other leg, the wires being joined at the apex of the 90* angle formed by the legs of the device.

United States Patent 1 Ridings, J r. 7

H 1 3,714,568 Jan. 30, 1973 [54] VARIABLE METER SHUNT [76] inventor: Willis A. Ridings, Jr., P. O. Box

236, Fort Supply, Okla 73841 [22] Filed: Sept. 21,197]

211 Appl. No.: 182,363

[52] U.S. Cl. 324/126, 338/150, 338/160 [51] Int. Cl. ..G0lr 1/00, H0lc 5/00 [58] Field of Search ..324/l26;v338/68, 118, 128,

[56] References Cited l,ll4,5l5 l0/l9l4 Pratt ..324/|26X Primary Examiner-Alfred E. Smith [57] ABSTRACT the apex of the 90 angle formed by the legs of the device.

UNITED STATES PATENTS 4 Claims, 3 Drawing Figures 1,008,326 ll/l9ll Grigsby ..338/92 X /5 E I a VARIABLE METER SHUNT This invention relates to electrical devices for direct reading meters, and more particularly to a variable meter shunt.

it is therefore the primary purpose of this invention to provide a variable meter shunt which will consist of a slotted and L-shaped plastic member which will be received upon the posts of the meter in order that the meter may cover an exact current range.

Another object of this invention is to provide a meter shunt device which will include a low resistance wire and a high resistance wire, each being carried upon a leg of the device, the wires being joined at the apex portion of the device so as to enable the device to be used for different resistance ratios between the legs of the device.

Still another object of this invention is to provide a device of the type described of which one face will be concaved so as to insure a slight pressure to be maintained with the terminal post nut fasteners, thus assuring continuity through the shunt device during adjustment in order to protect the meter while enabling the user to be able to move the device into position with the fingers of the users hand.

Yet another object of this invention is to provide a device of the type described which when attached to the terminals of a current indicating milliammeters will increase its range of current indication by shunting or by-passing a portion of the current through the wire portions of the legs of the device and mechanical adjustment is effected by sliding the post terminals of the meter to different positions within the slot portions of the shunt device.

Other objects of the present invention are to provide a variable meter shunt which is simple in design, inexpensive to manufacture, rugged in construction, easy to use and efficient in operation.

These and other objects will become readily evident upon a study of the following specifications together with the accompanying drawing wherein:

HO. 1 is a plan view of the present invention;

FIG. 2 is a rear view of a meter showing the device in place thereon; and

FIG. 3 is an enlarged cross-sectional view taken along the line 3-3 of H6. 2.

According to this invention, a variable meter shunt is shown to include a plastic body 11 consisting of legs 12 and 13, each of which has been secured thereto and embedded therein a low resistance wire 14 and a high resistance wire 15 which are joined at the apex 15 so as to form a variable resistance shunt. The body 11 of device 10 includes a continuous slot 16 in which is slideable a terminal 17. The face 18 is concaved so as to encroachingly engage against the washer 19 on the terminals 17 thus enabling it to be easily moved from one position to the other so as to change the current range of the meter 22.

The nut fastener 20 serves as hold-down means to provide continuity between the wires 14 and 15 and the nut 21 serves as locking means for nut 20.

It will be noted that either one of the wires 14 or 15 may be a low resistance wire while the other will be the high resistance wire and device 10 may be adaptable for conversion of surplus meters which are used by radio amateurs, experimenters and the like.

What I now claim is: l. A variable meter shunt for application to milliameters and the like, comprising an L'shaped plastic body, a low resistance wire and a high resistance wire carried by and embedded within said body so as to provide shunt means for said meter in a proper ratio for the equipment being used thereon, and slots formed in said body for receiving the terminal posts of said meter in order to slide said shunt thereon to obtain the proper current ratio.

2. A combination according to claim 1, wherein said L-shaped body includes a concaved face, said concave face serving to encroach upon the washers beneath the nut fasteners on said terminal so as to enable said shunt to be slid easily to obtain the proper position for the desired current change and said washer of said terminals engages said wires embedded within grooves of said concave face and thus causes said wires to have continuity, said wires being joined at the apex portion of said body and current flows through said washer, said wires of said shunt through said terminals to provide shunt means thereof.

3. A combination according to claim 2, wherein said slot through said body is parallel with said wires embedded within said bodyand said slot is continuous through both of said legs formed by the shape of said body so that various positions may beobtained to adjust various type meters.

4. A combination according to claim 3, wherein said washers of said terminals are in sliding engagement with said wires of said legs of said shunt so as to provide current transfer means for said shunt in shunting said meters and when said adjustment is made final, said nut fastener engaging said washer may be locked in position by the second nut fastener abutting with said first nut abutting with said first nut fastener upon said terminals of said meter. 

1. A variable meter shunt for application to milliameters and the like, comprising aN L-shaped plastic body, a low resistance wire and a high resistance wire carried by and embedded within said body so as to provide shunt means for said meter in a proper ratio for the equipment being used thereon, and slots formed in said body for receiving the terminal posts of said meter in order to slide said shunt thereon to obtain the proper current ratio.
 1. A variable meter shunt for application to milliameters and the like, comprising aN L-shaped plastic body, a low resistance wire and a high resistance wire carried by and embedded within said body so as to provide shunt means for said meter in a proper ratio for the equipment being used thereon, and slots formed in said body for receiving the terminal posts of said meter in order to slide said shunt thereon to obtain the proper current ratio.
 2. A combination according to claim 1, wherein said L-shaped body includes a concaved face, said concave face serving to encroach upon the washers beneath the nut fasteners on said terminal so as to enable said shunt to be slid easily to obtain the proper position for the desired current change and said washer of said terminals engages said wires embedded within grooves of said concave face and thus causes said wires to have continuity, said wires being joined at the apex portion of said body and current flows through said washer, said wires of said shunt through said terminals to provide shunt means thereof.
 3. A combination according to claim 2, wherein said slot through said body is parallel with said wires embedded within said body and said slot is continuous through both of said legs formed by the shape of said body so that various positions may be obtained to adjust various type meters. 